The SeaMAC and Route 56 APIs for these devices provide application software with tight control of the devices behavior. These APIs allow software applications to implement any higher-level SDLC behaviors as needed, as well as implement non-SDLC protocols that conform to the low-level behaviors of SDLC mentioned above. HDLC, PPP, Frame Relay, and X.25 protocols all conform to these low-level behaviors. Other protocols derived from HDLC commonly do so as well.